Mothusi Setshelenyane left home at 6pm on Saturday for a tortuous bus journey. Arriving in Bloemfontein at 4am on Sunday , he wasn't thinking about sleep. He wouldn't miss this party for the world.

"Under apartheid, black people could not do anything. Now we can," said the odd job man, 30, from a small town in the vast, arid Northern Cape. "We got democracy through the African National Congress (ANC). You must respect the ANC."

Africa's first liberation movement turned 100 years old on Sunday with a birthday celebration of song and dance, vuvuzelas and fireworks and a unity of purpose now too often lost in the day-to-day of South African politics.

This was a party yearning to rewalk the sunlit uplands of 1994, when millions queued patiently to vote for the first time and South Africa seemed able to defy political gravity.

The heroic struggle against a racist regime was remembered: those thousands who sacrificed their lives in a quest for human rights and democracy that took more than eight decades. So too Nelson Mandela's peerless act of forgiveness and reconciliation.

To spoil a centenarian's birthday party with talk of more recent corruption, cronyism and factionalism would have been churlish. To speak of the deepening cancer of unemployment and inequality would have been to revive a family pain it knows too well. More polite for now, perhaps, to put it as Mandela did in Long Walk to Freedom: "After climbing a great hill, one only finds that there are many more hills to climb."

For on this day, largely in blazing summer heat that made unhatted foreheads glisten, no one could deny the ANC its moment in the sun.

From all over the country, tens of thousands had come to the ANC's birthplace, Bloemfontein. They joined foreign heads of state and dignitaries at the Free State Stadium where, 18 months ago, Germany beat England 4-1 in the football World Cup. On Sunday the atmosphere was no less boisterous but the stands flowered with ANC black, green and gold.

The party flag and logo, with the legends "Unity in diversity" and "100 years of selfless struggle", were painted on the pitch. Either side of a central stage stood giant tent stands bearing monochrome photos of each of the ANC's 12 presidents.

First was John Dube, his sweeping walrus moustache and suit and tie hinting at the party's origins among a missionary-educated black elite. Number eight was Albert Luthuli, the first African winner of the Nobel Peace prize in 1960.

Then there was Oliver Tambo and the only living president not in attendance, Mandela, who is just seven years younger than the ANC. "He is in good spirits but very, very old," said Gwede Mantashe, the party's secretary-general, explaining the great man's absence.

Mandela himself was the first to acknowledge the party as bigger than any individual. Barend Petersen, 51, a businessman who travelled from Cape Town to be here, said: "It would have been an exceptional moment to see him in person attending the celebration. On the other hand, he is still with us in spirit and with us in life, and he is the iconic glue that represents the best of the ANC."

The 11th president, Thabo Mbeki, had come out of the cold to attend his first ANC event since he was acrimoniously ousted in 2008. He swallowed his pride to hand over a giant "centenary flame" to his usurper, Jacob Zuma, in what the party must hope will be a metaphorical healing of its deepest wound.

Other Zuma foes on stage included Winnie Madikizela-Mandela, the former president's ex-wife, and Julius Malema, the renegade youth league leader fighting suspension and denied a chance to speak.

Zuma began with a lap of honour and was then introduced by a traditional imbongi, or praise singer, to deliver a speech billed as one of the most important of his political life.

He paid tribute to Mandela and Mbeki and spoke of the anniversary as a national event, "a joyous celebration for all the people of South Africa". Recalling the difficult decision to pursue armed struggle, Zuma said: "Our freedom was definitely not free. It was achieved through the blood, sweat and tears of many selfless leaders and cadres of the movement."

Looking forward, Zuma said: "As we mark the ANC centenary, this is the right moment to pause and ponder the future of South Africa and of the ANC over the next 100 years. We must ask and answer the difficult questions about the future of our country. We must bring new energy and new ideas into the kind of society we want to build over the next few decades …We call on all our South Africans to join in a national dialogue on the future of the country."

The party's membership now tops a million, he announced. But by the time Zuma finished with a singalong and the cutting of a centenary cake, thousands had already left the 48,000-capacity stadium, like fans deserting a losing football team. The speech was quickly derided as sleep-inducing on Twitter. With almost unbearable symbolic timing, suddenly winds gusted and dark clouds gathered as ANC leaders drank champagne on stage.

Earlier, expectations had been raised by a pop concert. A male singer in leopardskin singlet and headband duetted with a shaven-headed female in a tiny yellow dress, while dancers in black, green and gold gyrated to an "ANC" ditty. There were traditional African chants and cheers as party stalwarts took the stage for the national anthem and interfaith prayers.

It was a day of pride for all but a few naysayers. The opposition Democratic Alliance sent congratulations and a delegation. Earlier, Archbishop emeritus Desmond Tutu, who recently threatened to pray for the ANC's downfall, had come to the party when a Wesleyan church was reconsecrated, 100 years to the day after the founding fathers met there.

Tutu shared a joke with Zuma as water was thrown against the church door, then sat beside him and American civil rights leader Jesse Jackson on the pews within. At midnight he watched with amusement as Zuma lit the centenary flame, at the second attempt, with some help from a man in blue overalls marked "Explosives".

Hymns were sung and a candle lit in memory of the ANC's presidents. But the sacred air was rent somewhat by an unseemly scramble at the door and the late entry of several African leaders and chieftans, forced to break from a gala dinner that overran until 3am.

There were tributes to the ANC from the rest of Africa and beyond. Armando Guebuza, president of Mozambique, told the gala dinner: "What you did made us proud of being Africans." Uganda's president Yuweri Museveni described the ANC centenary as "an achievement for the entire African continent".

British prime minister David Cameron wrote in a letter to Zuma: "The African National Congress has been a beacon for the world in the fight against discrimination and the struggle for freedom from oppression."

The weekend of celebrations had begun in Bloemfontein with a golf tournament at a club where, just a generation ago, black people were banned from playing except on Sundays. In a nod to African ritual, a spear-wielding Zuma led the slaughter of a black bull in an early morning cleansing ceremony. On Saturday, a performer collapsed and died during the cultural programme.

Piquantly, Bloemfontein, the former Boer capital of the Orange Free State, was also the birthplace of the National party and, incidentally, Lord of the Rings author JRR Tolkien. A century ago black washerwomen doing laundry for its white middle class were forced to carry 13 permits. But on Sunday, the city filled with songs of freedom, with Che Guevera berets and shirts, with cadres and comrades and cries of "Amandla!" and "Viva ANC!" – embers in the afterglow of a history well lived.